OMFO is an acronym of an exclamation of surprise where the terminal "O" stands for "Obama"; namely "Oh My Fucking Obama". OMFO is derivative of similar acronyms where either "God" (OMFG)or "Science" (OMFS)is used as the the terminal pro/noun.

As used in text based electronic communication: "OMFO! I can't believe (insert something you can't believe here)!"